阿达滩盆地古近纪淡水腹足类化石的发现及其地质意义

东昆仑西段阿达滩盆地早新生代陆相碎屑岩沉积建造，原先被笼统认为属“下第三系”。1：25万库郎米其提幅区调中，在该碎屑岩建造中首次发现淡水腹足类化石：假菊石型南方圆螺黄河亚种Australorbis pseudoammonius huanghoensis Yu，实椎螺(未定种)Lymneasp．根据含化石地层的岩相特征及腹足类化石生存时代，阿达滩盆地的下第三纪应属古近纪渐新世的干柴沟组下部，据该套地层的存在及不整合覆盖于其上的早更新世七个泉组分析，推断阿达滩盆地在渐新世末存在一次较强规模的隆起。     

添加钢筋提高隔震结构高宽比限值的研究

提出了在边支座上添加竖向钢筋以提高隔震结构高宽比限值的构造措施；从方案的构造、添加钢筋的工作状态以及对隔震效果的影响等方面论证了该措施的可行性；基于《建筑抗震设计规范》(GB50011-2001)，推导了添加竖向钢筋后隔震结构高宽比限值的公式；可行性论证和实际算例的计算结果表明，本方案技术可行、效果显著。     

Dynamic behavior and applicability of lead alloy absorber

Introduction As the result of economic development, metropolitans spring out in China. In metropolitans,the cities contact with each other through life line systems, the density of population is larger thanother areas, and social treasure in the unit area is much higher than other cities (GAO, 2003). Atthe same time, the risk of potential earthquake disaster in metropolitans increases greatly. One ofcharacters of metropolitan earthquake damage is that each city in the metropolitan will …     

Seismicity research in the subregions of Chinese mainland using strain accumulating and releasing model based on G-R relation

Introduction Earthquake activity analysis in different sub-regions in Chinese mainland shows that the dis- tribution of strong earthquakes exhibits the different spatial patterns in different periods. Seismic activity in the same earthquake area or seismic belt is self-similar to some extent, and the charac- teristic in time is some ″periodicity-like″. It shows that the frequency and intensity are quite dif- ferent in different periods (SHI et al, 1997). For a seismic region, strain is one…     

渭北东部奥陶灰岩地下水硫酸盐起源的化学同位素研究

通过对渭北东部奥陶灰岩地下水中SO42-、δD、δ34S、δ18O的分析研究,认为奥陶灰岩地下水中硫酸盐起源主要为海相硫酸盐的溶解,其次为南部古沉积咸水混入.     

Cosmogenic nuclide chronology of pre-last glacial maximum moraines at Lago Buenos Aires, 46°S, Argentina

At Lago Buenos Aires, Argentina, ¹⁰Be, ²⁶Al, and ⁴⁰Ar/³⁹Ar ages range from 190,000 to 109,000 yr for two moraines deposited prior to the last glaciation, 23,000–16,000 yr ago. Two approaches, maximum boulder ages assuming no erosion, and the average age of all boulders and an erosion rate of 1.4 mm/10³ yr, both yield a common estimate age of 150,000–140,000 yr for the two moraines. The erosion rate estimate derives from ¹⁰Be and ²⁶Al concentrations in old erratics, deposited on moraines that are >760,000 yr old on the basis of interbedded ⁴⁰Ar/³⁹Ar dated lavas. The new cosmogenic ages indicate that a major glaciation during marine oxygen isotope stage 6 occurred in the mid-latitude Andes. The next five youngest moraines correspond to stage 2. There is no preserved record of a glacial advance during stage 4. The distribution of dated boulders and their ages suggest that at least one major glaciation occurred between 760,000 and >200,000 yr ago. The mid-latitude Patagonian glacial record, which is well preserved because of low erosion rates, indicates that during the last two glacial cycles major glaciations in the southern Andes have been in phase with growth and decay of Northern Hemisphere ice sheets, especially at the 100,000 yr periodicity. Thus, glacial maxima are global in nature and are ultimately paced by small changes in Northern Hemisphere insolation.     

A Multi-cycle Climatic Fluctuation Record of the Last Interglacial Period:Typical Stratigraphic Section in the Salawusu River Valley on the Ordos Plateau,China

The Last Interglacial Period strata in the Milanggouwan section in the Salawusu River valley on the Ordos Plateau, China, have 8.5 sedimentary cycles composed alternately of eolian dune sands, fluvio-lacustrine facies and paleosols. Based on comprehensive analyses on the distribution of magnetic susceptibility and CaCO3 and paleo-ecology indicated by fossils in the region, it is considered that the sedimentation cycles resulted from dry-cold and warm-humid climate fluctuations. Magnetic susceptibility values and CaCO3 contents in stratigraphic sectors Ⅰ, Ⅲ, Ⅴ and Ⅱ, Ⅳ basically respectively present peaks and low vales, and the former three can in time correlate with MIS5a, MIS5c and MIS5e successively and the latter two with MIS5b and MIS5d. In addition, some horizons of eolian dune sands and the low vales of their magnetic susceptibility and CaCO3 are also correlated with 6 periods of cooling events indicated by the higher content of foraminifer Neogloboquadrina pachyderma (S.) documented in the V29-191 drill in the North Atlantic and the cold events recorded by δ^18O in the ice cores in GRIP, especially with 9 periods of dust events in Chinese Loess Plateau.     

新疆沙尘天气的演化特征及影响因子

利用1961-2003年新疆90个气象站地面观测资料,分析了新疆沙尘天气的空间分布特征及演变规律,并构建多元线性回归沙尘因子模型,探讨了气温、气温日较差、气压、平均风速、降水量对沙尘天气的影响程度.新疆沙尘天气的高发区在塔克拉玛干沙漠及南缘,年沙尘日数南疆是北疆的7倍.沙尘天气的高发时段在3～9月,43年内呈明显递减趋势.北疆、南疆沙尘天气的历史演变有着较好的10～15年和8～10年的振荡周期.北疆沙尘天气的主要影响因子是平均风速和气温日较差、降水量,春季明显受气温和平均风速的影响,夏季主要受平均风速和气温日较差的影响.南疆平均风速和降水量的影响占主导地位,春季气温日较差的影响也比较显著.另外,南疆春季沙尘天气对日照时数有着显著的影响.     

乡村旅游开发与老年人环境感知的关系

在浙江省余姚市大岚镇柿林村国家4A级景区对29位老人与43位非老人进行分组问卷调查，对老年组与非老年组的自然环境感知、经济环境感知、社会关系感知、旅游及游客感知差异进行卡方检验（X^2）．结果表明，两组人群对环境感知存在着明显差异．乡村旅游地老年人环境感知具有较强烈的乡土意识、对游客与旅游开发普遍持积极的支持态度、希望承担旅游地主人的角色、希望更多分享旅游带来的经济利益等特点．从旅游地老年人这一特殊人群的角度证实了旅游地居民支持旅游发展9个要素的结论，同时发现了中国老人的一些不同之处，提出了期待期的概念，提出从物质和精神两个层面入手，实现乡村旅游可持续发展的建议．     

基于GIS对新安江模型的改进初探

新安江模型能较好解决降雨时空分布问题,但忽略了其他分布不均的影响。流域汇流特征在很大程度上取决于流域形状特征和地形分布。提出一种方法,利用数字高程模型(DEM)划分子流域,提取各单元流域的平均坡度和最大汇流路径长度,以最大汇流路径长度推求形状系数,并将形状系数和平均坡度引入模型结构中,建立其与汇流参数之间的相关关系,使新安江模型能同时考虑降雨、流域形状以及地形分布。将改进后的模型应用于沿渡河流域进行验证,效果良好。